Globe for electric-arc lamps.



T. STAVE.

GLOBE FOR ELECTRIC ARC LAMPS. APPLICATION FILED 050.23. 1912.

PatentedJuly 31, 1917.

F INVENTOR W|TNESSESi ATTORNEY UNITED STATES PATENT FFICE.

THEODORE STAVE, OF NEW YORK, N. Y., ASSIGNOR TO WESTINGHOUSE ELECTRIC 85MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

GLOBE FOR ELECTRIC-ARC LAMPS.

Specification of Letters Patent.

Patented July 31, 191'7.

Application filed December 23, 1912. Serial No. 738,239.

To all whom it may concern Be it known that I, THEODORE STAvn, a subjectof the King of Italy, and a resident of New York, borough of Manhattan,county and State of New York, have made a new and useful Invention inGlobes for Electric- Arc Lamps, of which the following is aspecification.

My invention relates to globes for inclosed arc lamps and particularlyto those employing smoke producing carbons or electrodes, and has forits object, a more complete prevention of the deposit of the products ofcombustion evolved from the are, on the inner surface of the globe. I amaware that various means have been suggested to avoid such deposits,among which I may particularly mention the provision of a condensingchamber located immediately above the inclosing glass globe and in freecommunication therewith, the principle being to cause the combustionproducts to ascend and condense by virtue of the difference in temperature between the combustion chamber and the condensing chamber.

It has been found, however, that this purpose is not properlyaccomplished, particularly in cases where are lamps are subject tosevere climatic conditions and where sudden changes in the temperatureof the atmosphere occur. The cooling elfect of the outside air on theglobe is such as to materially interfere with the above-mentionedcondensing principle; causing the globe to be partially clouded duringthe time that the lamp is in operation and particularly toward the endof the trim.

I am aware that it has been suggested that this difficulty could beovercome by the use of an outer globe and an inner globe, but even thisarrangement has been found to be far from satisfactory, because the airin the space between the inner globe and the outer globe will carry awaya considerable amount of heat from the inner globe to the outer globe byconvection. I propose to minimize the total dissipation of heat from theinner globe by using a globe with double walls and having the spacebetween these two walls more or less completely evacuated of air.

By my construction the only dissipation of heat from the inner wall ofthe globe to the outer wall is caused by radiation and, therefore, thetemperature in the chamber formed by the inner walls of the globe iskept approximately constant and higher than that of the similar globe ofthe usual construction, and for the same reason very considerablechanges in temperature in the outside atmosphere will but very slightlyaffect the inner wall of the globe.

The result of my construction will be the greatest possible differenceof temperature between the arc inclosing chamber and the condensingchamber at all times. This will cause a very much larger percentage ofthe hot vapors and fumes to flow into the condensing chamber and,therefore, leave the inner wall of the glass globe far more free fromdeposits than would any other known construction.

My invention will be understood by re ferring to the accompanyingdrawings, in which,

Figure 1 shows in side elevational view the mechanism inclosing part ofa flaming arc lamp with its condensing chamber in dotted lines, theimproved form of my invention being shown in sectional lines and themeans of attaching the same to the base of the lamp in full lines.

Fig. 2 is a detail sectional view of the lower base plate or ring of alamp forming part of the condenser, such as is shown in Fig. 1 with myinvention attached.

Referring now to the drawings and first to Fig. 1, a and (5 represent aglobe with double walls and of integral structure secured to the baseplate or ring 0 of a flaming arc lamp having the usual form ofcondensing chamber C for collecting the particles of the products ofcombustion as they ascend, said globe being secured to the base plate orring 0 by a bail or holding device 7 of well lmown form and in the usualmanner. This double wall globe is preferably madeof the form shown inFig. 1,- the inner wall being preferably of the form of a frustum of acone and adapted to directly and closely surround the carbons of the arclamp (not shown) the outer wall a being substantially the form shown inFig. 1, so as to distribute the light with the best elfect. These twowalls, inner and outer, are molded into one integral globe and providedwith a well known exhaust extension 2' which, after the air is exhaustedbetween the inner and outer walls to the desired degree of rarity, issealed ofi? as shown. It is then adapted to be secured to the base plateor ring 0 which is provided with a carefully machined surface againstwhich the upper portion of the globe fits with accurate nicety. b is aring or extension integral with the base plate and against which theouter wall a of the globe rests, thus preventing displacement, parts ofthe base plate 0 and upper part of the globe a(Z being ground so as tomake the best possible air tight j oint on the upper surface; the globeis then secured to the lamp base in the usual manner by the bail Havingthus described my invention what I claim and desire to secure by LettersPatent of the United States is 1. In a flaming arc lamp, the combinationwith a member having a condensing chamber and embodying an annular baseportion, of an integral double-walled evacuated globe having an annularupper portion engaging said annular base portion and making a tightjoint therewith.

2. In a flaming arc lamp, the combination with a member havinga-condensing chamber, of a double-walled evacuated globe detachablypositioned in intimate engagement with the bottom of said member formaintaining a relatively high temperature in the space within saidglobe.

3. In a flaming arc lamp, the combination with a member having acondensing chamber and embodying a fiat annular bottom surface, of adetachable double-walled evacuated globe having a fiat annular topsurface adapted to register said flat annular bottom surface of saidmember to provide a tight joint between said member and said globe.

4:. A globe for are lamps comprising an open-ended integral memberhaving spaced outer and inner walls between which the air is exhausted,said globe being provided with a flat annular surface at its open end.

5. A double walled globe for flaming arc lamps, the walls being locatedone Within the other, the inner wall being substantially in the form ofa frustum of a cone, and the outer wall of substantially spherical form,the space between the walls being substantially exhausted of air.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THEODORE STAVE.

WVitnesses:

C. J. KINTNER, M. F. KEATING.

Copies of this patent may be obtained for five cents each, by addressingthe Gommissionei' of Patents, Washington, D. C.

